Detection rules › Kusto

Wazuh - Large Number of Web errors from an IP

Severity
low
Time window
1d
Group by
HostName, SourceIP
Author
Jordan Ross
Source
github.com/Azure/Azure-Sentinel

'Identifies instances where Wazuh logged over 400 '403' Web Errors from one IP Address. To onboard Wazuh data into Sentinel please view: https://documentation.wazuh.com/current/cloud-security/azure/index.html'

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1110 Brute Force

Rule body kusto

id: 2790795b-7dba-483e-853f-44aa0bc9c985
name: Wazuh - Large Number of Web errors from an IP
description: |
  'Identifies instances where Wazuh logged over 400 '403' Web Errors from one IP Address. To onboard Wazuh data into Sentinel please view: https://documentation.wazuh.com/current/cloud-security/azure/index.html'
severity: Low
requiredDataConnectors: []
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CredentialAccess
relevantTechniques:
  - T1110
query: |
  CommonSecurityLog
  | where DeviceProduct =~ "Wazuh"
  | where Activity has "Web server 400 error code."
  | where Message has "403"
  | extend HostName=substring(split(DeviceCustomString1,")")[0],1)
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), NumberOfErrors = dcount(SourceIP) by HostName, SourceIP
  | where NumberOfErrors > 400
  | sort by NumberOfErrors desc
  | extend timestamp = StartTime
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: HostName
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIP
version: 1.0.5
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Jordan Ross
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Networking" ]

Stages and Predicates

Stage 1: source

CommonSecurityLog

Stage 2: where

| where DeviceProduct =~ "Wazuh"

Stage 3: where

| where Activity has "Web server 400 error code."

Stage 4: where

| where Message has "403"

Stage 5: extend

| extend HostName=substring(split(DeviceCustomString1,")")[0],1)

Stage 6: summarize

| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), NumberOfErrors = dcount(SourceIP) by HostName, SourceIP
Threshold
gt 400

Stage 7: where

| where NumberOfErrors > 400

Stage 8: sort

| sort by NumberOfErrors desc

Stage 9: extend

| extend timestamp = StartTime

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Activitymatch
  • Web server 400 error code. transforms: term
DeviceProducteq
  • Wazuh
Messagematch
  • 403 transforms: term
NumberOfErrorsgt
  • 400 transforms: cased

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
EndTimesummarize
HostNamesummarize
NumberOfErrorssummarize
SourceIPsummarize
StartTimesummarize
timestampextend